It seems I own a little bit of everything from YMI, so I should weigh on Moyoaji's suggestion of the go/chess combo set
A few years ago I had seen a set like this available from the UK, and I suggested to Pong (YMI's owner) that it might be a neat set to offer to those of us who play both games with gusto!
Recently I bought one for myself as a "layaway" item from YMI on eBay for $10, and can offer the following observations:
1) The Chinese made chess set is very lightweight, heavily varnished, and not very aesthetically pleasing (frankly, downright ugly--I'm already looking at Indian weighted sets on eBay as replacements)
2) The Chinese made stones are indeed lightweight plastic, and again, not very exciting (I also purchased "layaway" Korean glass stones for $10 from YMI on eBay at the same time, to replace the provided plastic stones)
3) The board is simulated wood laminate with silk-screened chessboard on one side (1-7/8" squares, coordinates on the sides) and a Chinese-standard sized go board on the other. The magnets are very weak (you cannot pick up the board and have it stay together) but they have enough attraction to keep the two halves together when playing a game.
4) No case or bag is included, the chess and go pieces come in the ubiquitous white square YMI cardboard boxes.
The value to me is in the board, as I have the option of which game to play without having to lug two boards, and the cheapness of the board means I don't give it a second thought tossing it in a bag to take somewhere to play or study, with money left over to replace the vastly inferior parts with better quality.
Bottom line is that if you are seeking a *quality* portable go board I'd consider my other suggestions (above), but for something offbeat it may be worth considering. YMMV